2 * Copyright (C) 1994, David Greenman
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 * Copyright (c) 2007 The FreeBSD Foundation
7 * This code is derived from software contributed to Berkeley by
8 * the University of Utah, and William Jolitz.
10 * Portions of this software were developed by A. Joseph Koshy under
11 * sponsorship from the FreeBSD Foundation and Google, Inc.
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. All advertising materials mentioning features or use of this software
22 * must display the following acknowledgement:
23 * This product includes software developed by the University of
24 * California, Berkeley and its contributors.
25 * 4. Neither the name of the University nor the names of its contributors
26 * may be used to endorse or promote products derived from this software
27 * without specific prior written permission.
29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
41 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
47 #include "opt_capsicum.h"
48 #include "opt_ktrace.h"
49 #include "opt_kdtrace.h"
50 #include "opt_sched.h"
52 #include <sys/param.h>
54 #include <sys/capability.h>
55 #include <sys/kernel.h>
57 #include <sys/mutex.h>
58 #include <sys/pmckern.h>
61 #include <sys/pioctl.h>
62 #include <sys/ptrace.h>
63 #include <sys/resourcevar.h>
64 #include <sys/sched.h>
65 #include <sys/signalvar.h>
66 #include <sys/syscall.h>
67 #include <sys/syscallsubr.h>
68 #include <sys/sysent.h>
69 #include <sys/systm.h>
70 #include <sys/vmmeter.h>
73 #include <sys/ktrace.h>
75 #include <security/audit/audit.h>
77 #include <machine/cpu.h>
85 #include <vm/vm_param.h>
89 #include <security/mac/mac_framework.h>
92 * Define the code needed before returning to user mode, for trap and
96 userret(struct thread *td, struct trapframe *frame)
98 struct proc *p = td->td_proc;
100 CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
102 KASSERT((p->p_flag & P_WEXIT) == 0,
103 ("Exiting process returns to usermode"));
106 /* Check that we called signotify() enough. */
109 if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 ||
110 (td->td_flags & TDF_ASTPENDING) == 0))
111 printf("failed to set signal flags properly for ast()\n");
120 * If this thread tickled GEOM, we need to wait for the giggling to
121 * stop before we return to userland
123 if (td->td_pflags & TDP_GEOM)
127 * Charge system time if profiling.
129 if (p->p_flag & P_PROFIL)
130 addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio);
132 * Let the scheduler adjust our priority etc.
135 KASSERT(td->td_locks == 0,
136 ("userret: Returning with %d locks held.", td->td_locks));
138 /* Unfortunately td_vnet_lpush needs VNET_DEBUG. */
139 VNET_ASSERT(curvnet == NULL,
140 ("%s: Returning on td %p (pid %d, %s) with vnet %p set in %s",
141 __func__, td, p->p_pid, td->td_name, curvnet,
142 (td->td_vnet_lpush != NULL) ? td->td_vnet_lpush : "N/A"));
150 * Process an asynchronous software trap.
151 * This is relatively easy.
152 * This function will return with preemption disabled.
155 ast(struct trapframe *framep)
165 CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
167 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
168 WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
169 mtx_assert(&Giant, MA_NOTOWNED);
170 THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
171 td->td_frame = framep;
175 * This updates the td_flag's for the checks below in one
176 * "atomic" operation with turning off the astpending flag.
177 * If another AST is triggered while we are handling the
178 * AST's saved in flags, the astpending flag will be set and
179 * ast() will be called again.
182 flags = td->td_flags;
183 td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK |
184 TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND);
186 PCPU_INC(cnt.v_trap);
188 if (td->td_ucred != p->p_ucred)
189 cred_update_thread(td);
190 if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
191 addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
192 td->td_profil_ticks = 0;
193 td->td_pflags &= ~TDP_OWEUPC;
195 if (flags & TDF_ALRMPEND) {
197 kern_psignal(p, SIGVTALRM);
200 if (flags & TDF_PROFPEND) {
202 kern_psignal(p, SIGPROF);
206 if (flags & TDF_MACPEND)
207 mac_thread_userret(td);
209 if (flags & TDF_NEEDRESCHED) {
211 if (KTRPOINT(td, KTR_CSW))
215 sched_prio(td, td->td_user_pri);
216 mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL);
219 if (KTRPOINT(td, KTR_CSW))
225 * Check for signals. Unlocked reads of p_pendingcnt or
226 * p_siglist might cause process-directed signal to be handled
229 if (flags & TDF_NEEDSIGCHK || p->p_pendingcnt > 0 ||
230 !SIGISEMPTY(p->p_siglist)) {
232 mtx_lock(&p->p_sigacts->ps_mtx);
233 while ((sig = cursig(td, SIG_STOP_ALLOWED)) != 0)
235 mtx_unlock(&p->p_sigacts->ps_mtx);
239 * We need to check to see if we have to exit or wait due to a
240 * single threading requirement or some other STOP condition.
242 if (flags & TDF_NEEDSUSPCHK) {
244 thread_suspend_check(0);
248 if (td->td_pflags & TDP_OLDMASK) {
249 td->td_pflags &= ~TDP_OLDMASK;
250 kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0);
254 mtx_assert(&Giant, MA_NOTOWNED);
258 syscallname(struct proc *p, u_int code)
260 static const char unknown[] = "unknown";
261 struct sysentvec *sv;
264 if (sv->sv_syscallnames == NULL || code >= sv->sv_size)
266 return (sv->sv_syscallnames[code]);